BALANCING CELLS OF A TRACTION BATTERY USING STATISTICAL ANALYSIS

A vehicle includes a traction battery having a plurality of battery cells and a balance circuit configured to selectively discharge one or more of the battery cells. A controller is programmed to estimate charge capacities of the battery cells and determine a standard deviation of the estimated capacities. The controller is further programmed to determine a skewness of the estimated capacities. The controller is also programmed to, in response to the skewness exceeding a first threshold, command the balance circuit to discharge one or more of the battery cells when a state of charge (SOC) of the traction battery is less than a second threshold, and, in response to the skewness being less than the first threshold, command the balance circuit to discharge one or more of the battery cells when the SOC of the traction battery is greater than the second threshold.